1. Field of Invention
The invention relates, generally, to a chemical-mechanical polishing machine and, more specifically, to a chemical-mechanical polishing apparatus that includes an array of a plurality of the machine.
2. Description of Related Art
During large-scale integrated-circuit manufacturing, the planarization process of the deposition layer on a wafer is necessary and complex. Currently, the planarization process is performed by a chemical-mechanical polishing (CMP), and the chemical-mechanical polishing machine is a main apparatus for performing the chemical-mechanical polishing.
A conventional chemical-mechanical polishing machine includes generally a work table on which three polishing platens, a loading and unloading table, four polishing heads, and a cross-polishing-head support are mounted. Four cantilevers of the cross-polishing-head support absorb a polishing head, respectively, and two adjacent cantilevers are perpendicular to each other. A wafer absorbed by one polishing head should be polished on the three platens in sequence while a wafer to be polished absorbed by the polishing head located above the loading and unloading table waits for polishing. When the polishing of one of the wafers is finished, the polishing-head support rotates by 90 degrees so that the polishing head carrying the polished wafer rotates above the loading and unloading table and each of the other three polishing heads carrying wafers rotate above a next polishing platen, respectively, and, thus, perform the next polishing process for each of the wafers carried by the other three polishing heads. Each polishing head of the conventional chemical-mechanical polishing machine needs to move from a position above the polishing platen to another position above the loading and unloading table. During loading and unloading of the wafer, the center of one polishing head should be aligned with the center of the loading and unloading table, and the centers of the other three polishing heads for performing polishing should be aligned with the centers of the three polishing platens, respectively.
Therefore, high control accuracy is required. Moreover, the cross-polishing-head support of the conventional polishing machine is heavy in weight, complicated in structure, difficult in manufacturing, high in cost, and requires high precision. In addition, the four polishing heads on the cantilevers disadvantageously affect one another. For example, if there is something wrong with one of the polishing heads or the wafer carried thereby, the machine has to stop operation, thus decreasing the efficiency. The cantilevers of the cross-polishing-head support may magnify a “‘rotation’ position” error of the polishing-head support so that the polishing-head support is required to control with high precision for loading and unloading the wafer. In addition, the rotation error of the polishing-head support varies each time so that an adjusting of the polishing head position becomes more difficult.
Thus, there is a need in the related art for a chemical-mechanical polishing machine that solves at least one of these technical problems. More specifically, there is a need in the related art for such a machine that is simple in structure, easy to manufacture, and high in manufacturing efficiency and the requirement for control accuracy of which is low. There is a need in the related art also for a chemical-mechanical polishing apparatus that includes an array of a plurality of the machine.